While talking about PDF validation workflows we often come across questions like "Can I let the validation fail if the paper format does not match our corporate rules?". This and other customer specific requirements are indeed useful extensions to the pure file format and standard conformance tests.
Customer specific tests depend on whether the document was scanned or produced from a digital source and how it is intended to be used. For scanned documents the several checks could make sense.
Check out the checklist for scanned documents on our Expert Blog.